Updating a field from another DAC

Are you storing the SO OrderNbr in the UsrSONumber field?  If you are then you can add the PXDBScalar attribute to your UsrSOStatus column so that it reads the status field value from SOOrder.

What does your DAC field declarations look like for your custom fields?

@development93

In addition to what @ddunn  has mentioned, you can use FieldSelecting Event to retrieve the desired value from a DAC and show it in your custom/standard field of the current DAC. For example, below I have added a custom field (UsrClassName) to my GLTran (Lines of GL Transaction Screen) and shown the Account Class from the Account table for it. If you have the fields and the reference/current table in a DAC Extension you can use dacAlias.GetExtension<>() (also I have put in my code for your reference). You need to replace the pieces as per your need to make it.

// ********************* Display GL Account Class in GLTran *********************

using HCL;
using PX.Data;

namespace PX.Objects.GL
{
    // DAC Ext
    [PXNonInstantiatedExtension]
    public sealed class USRGLTranExt : PXCacheExtension<PX.Objects.GL.GLTran>
    {
        public static bool IsActive() => true;

        #region UsrClassName
        public abstract class usrClassName : PX.Data.BQL.BqlString.Field<usrClassName> { }
        [PXString(60, IsUnicode = true)]
        [PXUIField(DisplayName = "Account Class", Enabled = false, Visible = true)]
        public string UsrClassName { get; set; }
        #endregion
    }

    // Graph Ext
    public class USRJournalEntryExt : PXGraphExtension<PX.Objects.GL.JournalEntry>
    {
        public static bool IsActive() => true;

        protected void _(Events.FieldSelecting<GLTran, USRGLTranExt.usrClassName> e)
        {
            if (e.Row == null) return;

            e.ReturnValue = "";

            if (e.Row.AccountID != null)
            {
                Account account = PXSelect<Account,
                    Where<Account.accountID, Equal<Required<Account.accountID>>>>.Select(Base, e.Row.AccountID);

                if (account != null && account.AccountClassID != null)
                {
                    //Get any DAC Extension using below 1 line of code
                    MyAccountExt accountExt = accountExt.GetExtension<MyAccountExt>();

                    AccountClass accountClass = PXSelect<AccountClass,
                        Where<AccountClass.accountClassID, Equal<Required<AccountClass.accountClassID>>>>.Select(Base, account.AccountClassID);

                    if (accountClass != null)
                    {
                        e.ReturnValue = accountClass.Descr;
                    }
                }
            }
        }
    }
}

//Add the "UsrClassName" to the Transaction Grid (GLTranModuleBatNbr) in GL301000 and set the CommitChanges = True as follows:
//  <px:PXGridColumn DataField = "UsrClassName" Width="220" CommitChanges="True" />

So from the information I got here, tried to implement it on my code as shown below;
Getting the value of SOOrder status to UsrSoStatus;

strstatus?

see below;

The following code is not able to retrieve the status from SOOrder;

I’m thinking the issue starts from here;

I’m I doing it correctly?
Kindly assists.
I’m really stuck here.

I think @Django is right here, but it’s hard to give helpful code without seeing your field declaration. From what I can piece together, your PXDBScalar attribute might look like this:

[PXDBScalar(typeof(SearchFor<SOOrder.status>.
            In<SelectFrom<SOOrder>.
                Where<SOOrder.orderType.IsEqual<SOOrderTypeConstants.salesOrder>.
                    And<SOOrder.orderNbr.IsEqual<FSSODetExt.usrOrderNbr>>>>))]

This is F-Bql, which requires

using PX.Data.BQL.Fluent;